The Self-Reliance trait of the Individualism ideology does not appear to do what it says it does.  As shown in the first screen snapshot below, it says that "Citizens get +3 to their attributes".

So, I went to one of my planets (Mintor III) and looked at one of the citizens (Akil Schnell, second screen snapshot below on left) to see what their attributes were before applying the Self-Reliance trait.  Next, I applied the Self-Reliance trait then went back to see what impact it had on akil Schnell's attributes.  The third screen snapshot (on right) shows that nothing changed.  The fourth screen snapshot below shows that I really did apply the Self-Reliance trait.

Here is a link to a save file that will let you duplicate the steps I described above:

https://www.dropbox.com/scl/fi/0nd9cistdrlypv72p7btr/Trait-Issue-Under-1.60.457293.GC4Sav?rlkey=bf2whaw3bxcufvd57u9ntzwwk&dl=0